1. Field of the Invention
The present invention relates to a method of generating a hole or well in an electrically insulating or semiconducting substrate, and to a hole or well in a substrate generated by this method. The invention also relates to an array of holes or wells in a substrate generated by the method.
2. Description of the Related Art
WO 2005/097439 and WO 2009/059786 disclose methods of generating structures in substrates using the application of voltages to a substrate. The holes of these earlier applications, when present in arrays, typically require large distances (typically >1 mm) between adjacent holes to avoid flashovers during production of arrays without insulating layers. WO 2011/038788 and WO 2010/063462 disclose methods of generating structures in substrates using the application of voltages to a substrate which allows the fabrication of arrays of holes with small pitch (typically <1 mm). These methods are sometimes hampered by a destruction of the substrate surface due to the laser spot required for positioning the process location, or by a contamination of the surface due to incomplete ejection of material or redeposition on the surface around the holes generated.
Accordingly there is a need in the art to provide for improved methods allowing the generation of high quality holes and dense arrays thereof in substrates as well as a significant improvement of surface quality and controllability of hole parameters.